1. Field
This invention relates to the art of substrates, e.g., disk, micro-fabrication and, more particularly, to patterning of substrates, e.g., the magnetic layers of a hard disk for hard disk drives.
2. Related Art
Micro-fabrication of substrates is a well known art employed in, for example, fabrication of semiconductors, flat panel displays, light emitting diodes (LED's), hard disks for hard disk drives (HDD), etc. As is well known, fabrication of semiconductors, flat panel displays and LED's involves various steps for patterning the substrate. On the other hand, traditional fabrication of hard disks, generally referred to as longitudinal recording technology, does not involve patterning. Similarly, fabrication of disks for perpendicular recording technology does not involve patterning. Rather uniform layers are deposited and memory cells are generally defined by the alternating change of magnetic flux induced by the recording head, with each recording bit encompassing multiple grains within the unpatterned magnetic layers.
It has been demonstrated that non-patterned disks would fail to satisfy the needs of the market (e.g., bit density and costs) to remain competitive with other forms of storage. Consequently, it has been proposed that next generation disks should be patterned. It is envisioned that the patterning process may utilize photolithography, although currently there is no certainty which lithography technology may be commercialized, and no commercial system is yet available for commercial manufacturing of patterned media. Among contenders for photolithography are interference photolithography, near field lithography and nano-imprint lithography (NIL). Regardless of the lithography technology utilized, once the photoresist is exposed and developed, the disk needs to be etched and fabricated according to the desired pattern. However, to date much of the development efforts has been focused on the patterning step and no technology has been proposed for fabricating a patterned disk in a commercially viable environment.
To be sure, etch, sputtering, and other fabrication technologies are well known and well developed for semiconductor, flat panel display, LED's, etc. However, no system has been proposed for integrating these technology to enable fabrication of disks for HDD. Moreover, unlike HDD disks, in all of these other applications only one side of the substrate needs to be etched—allowing a chuck to hold the substrate from the backside during fabrication. On the other hand, HDD disks need to be fabricated on both sides, preventing the use of a chuck. Indeed, in HDD disk fabrication no part of the fabrication system may contact any surface of the disk. Also, while HDD manufacturers expect the system to have a throughput on the order of 1000 disks per hour, fabricators of semiconductors employ systems having throughputs of only tens of substrates per hour.
In view of the above, a method and system are required to enable fabrication of hard disks to provide patterned media for HDD.